Tim Samaras, his son and a colleague were all killed chasing a tornado this week. Most of us wouldn’t usually think of studying tornadoes as an “athletic” challenge, but watch this spectacular 2010 footage in which Tim is bloodied by hailstones. Maybe driving toward, and then dodging, a tornado funnel really isn’t so different from walking toward, and then dodging, a charging bull. I know, bullfighting is an art and more graceful. But both entail a lot of risk that gives danger junkies the thrill of their adventure and the relief of surviving each encounter…until you don’t…